1. Field of the Invention
The present invention relates to a swim fin structure including a fin portion with a pair of flukes transversely oriented relative to a foot attachment portion, so as to extend laterally outward from a wearer's foot, and formed from a material having sufficient flexibility to assume a variable configuration in conformance with a flow of water passing over an exposed surface thereof, such that a pocket-like structure is formed in each fluke, automatically adjusting to the flow of water in a manner which allows the pocket of each fluke to at least partially surround the water flow and be disposed in propelling engagement therewith, thereby substantially enhancing the propulsion capabilities to be achieved by a wearer of the swim fin structure.
2. Description of the Related Art
The use of swim fins to aid in propelling a swimmer through water has been in existence for many years. Typically, such swim fins come in pairs, such that a different swim fin is removably attached to each foot of the swimmer. For example, in typical fashion, known swim fin structures generally include a foot retaining structure having a generally hollow interior designed to receive at least a portion of the swimmer's foot therein. Additionally, the fin or propelling portion of traditional fins usually include substantially elongated configurations extending coextensively outward from a front portion of the foot retaining structure, with the overall fin being generally formed from a partially flexible material so as to provide somewhat of a "yielding-type" of resistance to the flow of water as the swimmer passes therethrough.
When utilizing a traditional pair of swim fins, the swimmer normally demonstrates a scissor-type kick or a flutter-type kick, characterized by the legs of the swimmer moving in substantially opposite directions and alternatively passing through both an up stroke and a down stroke. While such a flutter type kick is at least partially effective to aid the swimmer in being propelled through water, it is generally recognized that this type of kick exerts significant stress on the lower leg and ankle portion of the swimmer. Such excessive stress often times results in fatigue of the swimmer, and a diminishing of his or her performance, thereby at least partially defeating the purpose of utilizing swim fins.
With the increased popularity of water sports in general, and SCUBA diving in particular, numerous attempts have been made to increase the efficiency of swim fin structures by altering their overall structure and configuration, and in certain instances, varying the material from which conventional swim fin structures are normally formed. By way of example, one known and commercially available fin structure is commonly known as the "Force Fin", which incorporates a generally trapezoidal configuration and which includes a shoe portion having a hollow interior specifically dimensioned to allow a predetermined movement and/or flexing of the foot to aid the swimmer in the performance of the conventional flutter-type stroke. In this known type of swim fin structure, the muscles of the swimmer's foot are allowed to move, and in doing so are intended to assist the muscles of the lower leg to accomplish an alternate "kick and flip" type of movement of the fin during the performance of the aforementioned flutter kick. In addition, another known and commercially available swim fin structure is commonly referred to as the "Biofin" which is characterized by the fin portion having two segments separated by a generally elongated slot formed therein. This type of fin structure is also intended to be used when the swimmer performs the conventional flutter kick, wherein the fin, as is common with the vast majority of known or conventional swim fin structures, is alternately forced through the up and down strokes of the kick, utilizing the muscles of the lower leg, ankle and foot of the swimmer. Accordingly, it is generally recognized that utilization of known swim fin structures, including, but not limited to, the type of structures specifically set forth above, frequently results in a large amount of stress being placed on the ankle and/or lower leg, thereby frequently resulting in fatigue of the associated muscles of the swimmer, when such known or conventional swim fin structures are used for even a limited amount of time.
It is generally recognized that the human body, especially when traveling through water, such as when swimming or diving, is not very streamlined and thereby produces considerable drag and a significant path of "disturbed" water as the swimmer moves along an intended path of travel. When utilizing conventional or known swim fins, such as of the type set forth above, the alternating "flutter" type of kicking motion does not serve to most efficiently propel the swimmer through water. This is at least partially attributable to the fact that only one of the up and down strokes of the swimmer's legs serves as a propelling or driving stroke, wherein the other of the up and down strokes effectively serves as a "re-loading" stroke. The "re-loading" stroke, normally being the upwardly directed stroke, provides a minimum amount of propelling force in the direction of intended travel of the swimmer.
Based on the above disadvantages and recognized inefficiencies, there is a need in this area for an improved swim fin, which is capable of providing somewhat of a "gliding" effect and which serves to streamline the disturbed water or "wake" trailing the swimmer, by substantially directing the water, in somewhat of a spinning configuration, laterally outward, and to some extent, rearwardly away from an approximate center of the swimmer's path. In addition, an improved swim fin should also be capable of allowing the swimmer to demonstrate a more efficient "dolphin-type" stroke, resulting in a significantly decreased stress being placed on the ankle or lower muscles of the leg, due to less leverage being exerted thereon. Also, an improved swim fin structure, of the type set forth in greater detail hereinafter, should be capable of producing a propelling or driving stroke with both the upwardly directed stroke segment as well as the downwardly directed stroke segment of the kick being performed. The resulting double propelling motion would significantly increase the efficiency of movement and reduce the expended effort of the swimmer, when using such an improved swim fin structure. Further, in order to overcome the above noted disadvantages associated with conventional swim fins, at least one portion of such an improved swim fin structure should be formed of a semi flexible material which has sufficient structural integrity to demonstrate a "whiplike" action and further wherein an associated portion of the improved swim fin structure should be formed of a material having sufficiently greater flexibility. Such significantly greater flexibility would allow a fin portion to be substantially self adjusting and thereby assume a freely changeable or variable configuration, which at least partially conforms to the flow of water passing along or over exposed surfaces of the fin portion in a manner which effectuates a propelling or driving engagement thereof with the flow of water.